1. Field of the Invention
The present invention relates to a facsimile apparatus which sends or receives documents, as image data, from other facsimile apparatus through a commercial telecommunication line in accordance with a predetermined communication protocol. During the communication, a facsimile apparatus memorizes communication protocol data exchanged with another facsimile apparatus, and the facsimile apparatus outputs the communication protocol data as a monitor list in response to a request.
2. Description of the Related Art
A facsimile apparatus which is mostly used in offices and homes, may be a G III facsimile device or a G IV facsimile device. Most G III facsimile devices or G IV facsimile devices have a function which memorizes communication protocol data in a memory, step by step, until the facsimile transmission is ended. In general, a facsimile communication protocol follows Recommendation T.30 of the ITU-T (International Telecommunication Union-Telecommunication Sector). The communication protocol data shows a communication process history according to the communication protocol.
A maintenance person can obtain the communication protocol data as a monitor list outputted from the memory and can learn a status of the facsimile device from the monitor list when a communication problem occurs, even if some time passed since the problem. Thus, the maintenance person can take suitable action without waiting for the problem to repeat itself. However, it is extremely difficult in practice to specify exactly the time the communication problem occurred and the cause of the problem, and thus, it may take a long time until suitable action is taken.
A conventional method will be described with reference to FIG. 1. FIG. 1 shows a facsimile communication protocol in a multi-page transmission/reception in accordance with the ITU-T Recommendation T.30. In this instance, a sending station outputs a monitor list. The sending station is a facsimile device which sends a document while scanning the document.
In FIG. 1, the protocol prior to the transmission of a page of an image signal is not explained in detail. After a sending station sends a PIX signal (a page of the image signal), it further sends a PPS.multidot.MPS signal (a part-page signal.multidot.multi-page signal). The PPS.multidot.MPS signal informs a receiving station of the end of the PIX signal and the sending station will send the PIX signal for the next document. On the other hand, after the receiving station detects the PPS.multidot.MPS signal following the PIX signal, the receiving station detects the end of the PPS.multidot.MPS signal. When the receiving station detects reception ready status for the next document, the receiving station sends a MCF signal (a message confirmation signal) to inform the sending station of the correct reception of the previous document image signal, and the receiving station waits for the next PIX signal. The sending station detects the MCF signal, and when the sending station is ready to send the next document, the sending station starts to send the next PIX signal, as was done for the previous PIX signal. The above operation is repeated as long as the document to be transmitted exists.
FIG. 2 shows a case wherein a communication problem occurs during the facsimile transmission. In FIG. 2, the facsimile transmission is terminated by issuing a disconnect signal (a DCN signal) because the communication problem after a retrying action is experienced following a first PPS.multidot.MPS signal outputted from the sending station. In the retrying action, second and third PPS.multidot.MPS signals are outputted from the sending station if the sending station does not receive any response from the receiving station within a prescribed time from the output of the first PPS.multidot.MPS signal. The prescribed time is defined as "T4" by the ITU-T Recommendation T.30. If the response outputted from the receiving station is received by the sending station when the sending station outputs a second PPS.multidot.MPS signal, no further retrying action is executed.
Such communication processes are memorized into a random access memory (RAM), step by step, during the facsimile communication between the two facsimile devices. All of the data sent to or received from a facsimile device is stored in the memory during the facsimile communication.
When the maintenance person outputs a monitor list from the facsimile device, the contents stored in the memory are printed on a recording paper as a monitor list. A monitor list shows a presence of a communication problem and communication processes in the facsimile communication. However, it is difficult to specify the time when the communication problem occurred and the cause of the problem even if the monitor list is intensively inspected, because the monitor list gives some abbreviation of the signal in the facsimile communication.
According to the monitor list, in the above case, the maintenance person who has an abundant store of knowledge about the facsimile communication protocol can specify that the communication problem occurred at a point at which the DCN signal was issued instead of the MCF signal. This is because, if the communication is carried out normally, the MCF signal is issued after the PPS.multidot.MPS signal is issued.
However, it may be difficult in general to specify the cause of the communication problem from the monitor list even by the maintenance person. Incidentally, a T4 timer time-out in which the communication line is not connected after a prescribed time (T4) has passed at the third retrying action, an instantaneous breakdown of an electric current on the telephone circuit or a scanning paper jam in the facsimile device (the sending station) after transmitting the PPS.multidot.MPS signal three times may each be considered as a cause of the above communication problem. Since various possibilities are considered as a cause of the problem, it may take some time to specify a cause of the problem, and thus a suitable action in response to the problem will be late.